// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_FRAME_HOST_NAVIGATION_CONTROLLER_IMPL_H_
#define CONTENT_BROWSER_FRAME_HOST_NAVIGATION_CONTROLLER_IMPL_H_

#include <stddef.h>
#include <stdint.h>

#include <vector>

#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "content/browser/frame_host/navigation_controller_delegate.h"
#include "content/browser/frame_host/navigation_entry_impl.h"
#include "content/browser/ssl/ssl_manager.h"
#include "content/public/browser/navigation_controller.h"
#include "content/public/browser/navigation_type.h"
#include "content/public/browser/reload_type.h"

struct FrameHostMsg_DidCommitProvisionalLoad_Params;

namespace content {
class FrameTreeNode;
class RenderFrameHostImpl;
class NavigationEntryScreenshotManager;
class SiteInstance;
struct LoadCommittedDetails;

class CONTENT_EXPORT NavigationControllerImpl
    : public NON_EXPORTED_BASE(NavigationController) {
public:
    NavigationControllerImpl(
        NavigationControllerDelegate* delegate,
        BrowserContext* browser_context);
    ~NavigationControllerImpl() override;

    // NavigationController implementation:
    WebContents* GetWebContents() const override;
    BrowserContext* GetBrowserContext() const override;
    void Restore(int selected_navigation,
        RestoreType type,
        std::vector<std::unique_ptr<NavigationEntry>>* entries) override;
    NavigationEntryImpl* GetActiveEntry() const override;
    NavigationEntryImpl* GetVisibleEntry() const override;
    int GetCurrentEntryIndex() const override;
    NavigationEntryImpl* GetLastCommittedEntry() const override;
    int GetLastCommittedEntryIndex() const override;
    bool CanViewSource() const override;
    int GetEntryCount() const override;
    NavigationEntryImpl* GetEntryAtIndex(int index) const override;
    NavigationEntryImpl* GetEntryAtOffset(int offset) const override;
    void DiscardNonCommittedEntries() override;
    NavigationEntryImpl* GetPendingEntry() const override;
    int GetPendingEntryIndex() const override;
    NavigationEntryImpl* GetTransientEntry() const override;
    void SetTransientEntry(std::unique_ptr<NavigationEntry> entry) override;
    void LoadURL(const GURL& url,
        const Referrer& referrer,
        ui::PageTransition type,
        const std::string& extra_headers) override;
    void LoadURLWithParams(const LoadURLParams& params) override;
    void LoadIfNecessary() override;
    bool CanGoBack() const override;
    bool CanGoForward() const override;
    bool CanGoToOffset(int offset) const override;
    void GoBack() override;
    void GoForward() override;
    void GoToIndex(int index) override;
    void GoToOffset(int offset) override;
    bool RemoveEntryAtIndex(int index) override;
    const SessionStorageNamespaceMap& GetSessionStorageNamespaceMap()
        const override;
    SessionStorageNamespace* GetDefaultSessionStorageNamespace() override;
    bool NeedsReload() const override;
    void SetNeedsReload() override;
    void CancelPendingReload() override;
    void ContinuePendingReload() override;
    bool IsInitialNavigation() const override;
    bool IsInitialBlankNavigation() const override;
    void Reload(ReloadType reload_type, bool check_for_repost) override;
    void NotifyEntryChanged(const NavigationEntry* entry) override;
    void CopyStateFrom(const NavigationController& source) override;
    void CopyStateFromAndPrune(NavigationController* source,
        bool replace_entry) override;
    bool CanPruneAllButLastCommitted() override;
    void PruneAllButLastCommitted() override;
    void ClearAllScreenshots() override;

    // Whether this is the initial navigation in an unmodified new tab.  In this
    // case, we know there is no content displayed in the page.
    bool IsUnmodifiedBlankTab() const;

    // The session storage namespace that all child RenderViews belonging to
    // |instance| should use.
    SessionStorageNamespace* GetSessionStorageNamespace(
        SiteInstance* instance);

    // Returns the index of the specified entry, or -1 if entry is not contained
    // in this NavigationController.
    int GetIndexOfEntry(const NavigationEntryImpl* entry) const;

    // Return the index of the entry with the given unique id, or -1 if not found.
    int GetEntryIndexWithUniqueID(int nav_entry_id) const;

    // Return the entry with the given unique id, or null if not found.
    NavigationEntryImpl* GetEntryWithUniqueID(int nav_entry_id) const;

    NavigationControllerDelegate* delegate() const
    {
        return delegate_;
    }

    // For use by WebContentsImpl ------------------------------------------------

    // Allow renderer-initiated navigations to create a pending entry when the
    // provisional load starts.
    void SetPendingEntry(std::unique_ptr<NavigationEntryImpl> entry);

    // Handles updating the navigation state after the renderer has navigated.
    // This is used by the WebContentsImpl.
    //
    // If a new entry is created, it will return true and will have filled the
    // given details structure and broadcast the NOTIFY_NAV_ENTRY_COMMITTED
    // notification. The caller can then use the details without worrying about
    // listening for the notification.
    //
    // In the case that nothing has changed, the details structure is undefined
    // and it will return false.
    bool RendererDidNavigate(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
        LoadCommittedDetails* details,
        bool is_navigation_within_page,
        NavigationHandleImpl* navigation_handle);

    // Notifies us that we just became active. This is used by the WebContentsImpl
    // so that we know to load URLs that were pending as "lazy" loads.
    void SetActive(bool is_active);

    // Returns true if the given URL would be an in-page navigation (e.g., if the
    // reference fragment is different, or after a pushState) from the last
    // committed URL in the specified frame. If there is no last committed entry,
    // then nothing will be in-page.
    //
    // Special note: if the URLs are the same, it does NOT automatically count as
    // an in-page navigation. Neither does an input URL that has no ref, even if
    // the rest is the same. This may seem weird, but when we're considering
    // whether a navigation happened without loading anything, the same URL could
    // be a reload, while only a different ref would be in-page (pages can't clear
    // refs without reload, only change to "#" which we don't count as empty).
    //
    // The situation is made murkier by history.replaceState(), which could
    // provide the same URL as part of an in-page navigation, not a reload. So
    // we need to let the (untrustworthy) renderer resolve the ambiguity, but
    // only when the URLs are on the same origin. We rely on |origin|, which
    // matters in cases like about:blank that otherwise look cross-origin.
    bool IsURLInPageNavigation(const GURL& url,
        const url::Origin& origin,
        bool renderer_says_in_page,
        RenderFrameHost* rfh) const;

    // Sets the SessionStorageNamespace for the given |partition_id|. This is
    // used during initialization of a new NavigationController to allow
    // pre-population of the SessionStorageNamespace objects. Session restore,
    // prerendering, and the implementaion of window.open() are the primary users
    // of this API.
    //
    // Calling this function when a SessionStorageNamespace has already been
    // associated with a |partition_id| will CHECK() fail.
    void SetSessionStorageNamespace(
        const std::string& partition_id,
        SessionStorageNamespace* session_storage_namespace);

    // Random data ---------------------------------------------------------------

    SSLManager* ssl_manager() { return &ssl_manager_; }

    // Maximum number of entries before we start removing entries from the front.
    static void set_max_entry_count_for_testing(size_t max_entry_count)
    {
        max_entry_count_for_testing_ = max_entry_count;
    }
    static size_t max_entry_count();

    void SetGetTimestampCallbackForTest(
        const base::Callback<base::Time()>& get_timestamp_callback);

    // Takes a screenshot of the page at the current state.
    void TakeScreenshot();

    // Sets the screenshot manager for this NavigationControllerImpl. Setting a
    // NULL manager recreates the default screenshot manager and uses that.
    void SetScreenshotManager(
        std::unique_ptr<NavigationEntryScreenshotManager> manager);

    // Discards only the pending entry. |was_failure| should be set if the pending
    // entry is being discarded because it failed to load.
    void DiscardPendingEntry(bool was_failure);

    // Sets a flag on the pending NavigationEntryImpl instance if any that the
    // navigation failed due to an SSL error.
    void SetPendingNavigationSSLError(bool error);

private:
    friend class RestoreHelper;

    FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
        PurgeScreenshot);
    FRIEND_TEST_ALL_PREFIXES(TimeSmoother, Basic);
    FRIEND_TEST_ALL_PREFIXES(TimeSmoother, SingleDuplicate);
    FRIEND_TEST_ALL_PREFIXES(TimeSmoother, ManyDuplicates);
    FRIEND_TEST_ALL_PREFIXES(TimeSmoother, ClockBackwardsJump);

    // Used for identifying which frames need to navigate.
    using FrameLoadVector = std::vector<std::pair<FrameTreeNode*, FrameNavigationEntry*>>;

    // Helper class to smooth out runs of duplicate timestamps while still
    // allowing time to jump backwards.
    class CONTENT_EXPORT TimeSmoother {
    public:
        // Returns |t| with possibly some time added on.
        base::Time GetSmoothedTime(base::Time t);

    private:
        // |low_water_mark_| is the first time in a sequence of adjusted
        // times and |high_water_mark_| is the last.
        base::Time low_water_mark_;
        base::Time high_water_mark_;
    };

    // Causes the controller to load the specified entry. The function assumes
    // ownership of the pointer since it is put in the navigation list.
    // NOTE: Do not pass an entry that the controller already owns!
    void LoadEntry(std::unique_ptr<NavigationEntryImpl> entry);

    // Identifies which frames need to be navigated for the pending
    // NavigationEntry and instructs their Navigator to navigate them.  Returns
    // whether any frame successfully started a navigation.
    bool NavigateToPendingEntryInternal(ReloadType reload_type);

    // Recursively identifies which frames need to be navigated for the pending
    // NavigationEntry, starting at |frame| and exploring its children.  Only used
    // in --site-per-process.
    void FindFramesToNavigate(FrameTreeNode* frame,
        FrameLoadVector* sameDocumentLoads,
        FrameLoadVector* differentDocumentLoads);

    // Returns whether there is a pending NavigationEntry whose unique ID matches
    // the given NavigationHandle's pending_nav_entry_id.
    bool PendingEntryMatchesHandle(NavigationHandleImpl* handle) const;

    // Classifies the given renderer navigation (see the NavigationType enum).
    NavigationType ClassifyNavigation(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params) const;

    // Handlers for the different types of navigation types. They will actually
    // handle the navigations corresponding to the different NavClasses above.
    // They will NOT broadcast the commit notification, that should be handled by
    // the caller.
    //
    // RendererDidNavigateAutoSubframe is special, it may not actually change
    // anything if some random subframe is loaded. It will return true if anything
    // changed, or false if not.
    //
    // The NewPage and NewSubframe functions take in |replace_entry| to pass to
    // InsertOrReplaceEntry, in case the newly created NavigationEntry is meant to
    // replace the current one (e.g., for location.replace or successful loads
    // after net errors), in contrast to updating a NavigationEntry in place
    // (e.g., for history.replaceState).
    void RendererDidNavigateToNewPage(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
        bool is_in_page,
        bool replace_entry,
        NavigationHandleImpl* handle);
    void RendererDidNavigateToExistingPage(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
        bool is_in_page,
        bool was_restored,
        NavigationHandleImpl* handle);
    void RendererDidNavigateToSamePage(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
        NavigationHandleImpl* handle);
    void RendererDidNavigateNewSubframe(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
        bool is_in_page,
        bool replace_entry);
    bool RendererDidNavigateAutoSubframe(
        RenderFrameHostImpl* rfh,
        const FrameHostMsg_DidCommitProvisionalLoad_Params& params);

    // Actually issues the navigation held in pending_entry.
    void NavigateToPendingEntry(ReloadType reload_type);

    // Allows the derived class to issue notifications that a load has been
    // committed. This will fill in the active entry to the details structure.
    void NotifyNavigationEntryCommitted(LoadCommittedDetails* details);

    // Updates the virtual URL of an entry to match a new URL, for cases where
    // the real renderer URL is derived from the virtual URL, like view-source:
    void UpdateVirtualURLToURL(NavigationEntryImpl* entry,
        const GURL& new_url);

    // Invoked after session/tab restore or cloning a tab. Resets the transition
    // type of the entries, updates the max page id and creates the active
    // contents.
    void FinishRestore(int selected_index, RestoreType type);

    // Inserts a new entry or replaces the current entry with a new one, removing
    // all entries after it. The new entry will become the active one.
    void InsertOrReplaceEntry(std::unique_ptr<NavigationEntryImpl> entry,
        bool replace);

    // Removes the entry at |index|, as long as it is not the current entry.
    void RemoveEntryAtIndexInternal(int index);

    // Discards both the pending and transient entries.
    void DiscardNonCommittedEntriesInternal();

    // Discards only the transient entry.
    void DiscardTransientEntry();

    // If we have the maximum number of entries, remove the oldest one in
    // preparation to add another.
    void PruneOldestEntryIfFull();

    // Removes all entries except the last committed entry.  If there is a new
    // pending navigation it is preserved. In contrast to
    // PruneAllButLastCommitted() this does not update the session history of the
    // RenderView.  Callers must ensure that |CanPruneAllButLastCommitted| returns
    // true before calling this.
    void PruneAllButLastCommittedInternal();

    // Inserts up to |max_index| entries from |source| into this. This does NOT
    // adjust any of the members that reference entries_
    // (last_committed_entry_index_, pending_entry_index_ or
    // transient_entry_index_).
    void InsertEntriesFrom(const NavigationControllerImpl& source, int max_index);

    // Returns the navigation index that differs from the current entry by the
    // specified |offset|.  The index returned is not guaranteed to be valid.
    int GetIndexForOffset(int offset) const;

    // ---------------------------------------------------------------------------

    // The user browser context associated with this controller.
    BrowserContext* browser_context_;

    // List of |NavigationEntry|s for this controller.
    std::vector<std::unique_ptr<NavigationEntryImpl>> entries_;

    // An entry we haven't gotten a response for yet.  This will be discarded
    // when we navigate again.  It's used only so we know what the currently
    // displayed tab is.
    //
    // This may refer to an item in the entries_ list if the pending_entry_index_
    // == -1, or it may be its own entry that should be deleted. Be careful with
    // the memory management.
    NavigationEntryImpl* pending_entry_;

    // Navigations could occur in succession. This field holds the last pending
    // entry for which we haven't received a response yet.
    NavigationEntryImpl* last_pending_entry_;

    // If a new entry fails loading, details about it are temporarily held here
    // until the error page is shown (or 0 otherwise).
    //
    // TODO(avi): We need a better way to handle the connection between failed
    // loads and the subsequent load of the error page. This current approach has
    // issues: 1. This might hang around longer than we'd like if there is no
    // error page loaded, and 2. This doesn't work very well for frames.
    // http://crbug.com/474261
    int failed_pending_entry_id_;

    // The index of the currently visible entry.
    int last_committed_entry_index_;

    // The index of the pending entry if it is in entries_, or -1 if
    // pending_entry_ is a new entry (created by LoadURL).
    int pending_entry_index_;

    // The index for the entry that is shown until a navigation occurs.  This is
    // used for interstitial pages. -1 if there are no such entry.
    // Note that this entry really appears in the list of entries, but only
    // temporarily (until the next navigation).  Any index pointing to an entry
    // after the transient entry will become invalid if you navigate forward.
    int transient_entry_index_;

    // The index of the last pending entry if it is in entries, or -1 if it was
    // created by LoadURL.
    int last_pending_entry_index_;

    // The index of the last transient entry. Defaults to -1.
    int last_transient_entry_index_;

    // The delegate associated with the controller. Possibly NULL during
    // setup.
    NavigationControllerDelegate* delegate_;

    // Manages the SSL security UI.
    SSLManager ssl_manager_;

    // Whether we need to be reloaded when made active.
    bool needs_reload_;

    // Whether this is the initial navigation.
    // Becomes false when initial navigation commits.
    bool is_initial_navigation_;

    // Prevent unsafe re-entrant calls to NavigateToPendingEntry.
    bool in_navigate_to_pending_entry_;

    // Used to find the appropriate SessionStorageNamespace for the storage
    // partition of a NavigationEntry.
    //
    // A NavigationController may contain NavigationEntries that correspond to
    // different StoragePartitions. Even though they are part of the same
    // NavigationController, only entries in the same StoragePartition may
    // share session storage state with one another.
    SessionStorageNamespaceMap session_storage_namespace_map_;

    // The maximum number of entries that a navigation controller can store.
    static size_t max_entry_count_for_testing_;

    // If a repost is pending, its type (RELOAD or RELOAD_BYPASSING_CACHE),
    // NO_RELOAD otherwise.
    ReloadType pending_reload_;

    // Used to get timestamps for newly-created navigation entries.
    base::Callback<base::Time()> get_timestamp_callback_;

    // Used to smooth out timestamps from |get_timestamp_callback_|.
    // Without this, whenever there is a run of redirects or
    // code-generated navigations, those navigations may occur within
    // the timer resolution, leading to things sometimes showing up in
    // the wrong order in the history view.
    TimeSmoother time_smoother_;

    std::unique_ptr<NavigationEntryScreenshotManager> screenshot_manager_;

    // Used for tracking consecutive reload requests.  If the last user-initiated
    // navigation (either browser-initiated or renderer-initiated with a user
    // gesture) was a reload, these hold the ReloadType and timestamp.  Otherwise
    // these are ReloadType::NONE and a null timestamp, respectively.
    ReloadType last_committed_reload_type_;
    base::Time last_committed_reload_time_;

    DISALLOW_COPY_AND_ASSIGN(NavigationControllerImpl);
};

} // namespace content

#endif // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_CONTROLLER_IMPL_H_
